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Commit 8ce0bc69 authored by Pekka Korpinen's avatar Pekka Korpinen Committed by Greg Kroah-Hartman
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iio: dac: ad5446: Fix ad5622_write() return value 



commit 558df982d4ead9cac628153d0d7b60feae05ddc8 upstream.

On success i2c_master_send() returns the number of bytes written. The
call from iio_write_channel_info(), however, expects the return value to
be zero on success.

This bug causes incorrect consumption of the sysfs buffer in
iio_write_channel_info(). When writing more than two characters to
out_voltage0_raw, the ad5446 write handler is called multiple times
causing unexpected behavior.

Fixes: 3ec36a2c ("iio:ad5446: Add support for I2C based DACs")
Signed-off-by: default avatarPekka Korpinen <pekka.korpinen@iki.fi>
Link: https://lore.kernel.org/r/20210929185755.2384-1-pekka.korpinen@iki.fi


Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f01e16d3

drivers/iio/dac/ad5446.c

+8 −1
Original line number Diff line number Diff line
@@ -527,8 +527,15 @@ static int ad5622_write(struct ad5446_state *st, unsigned val) 
{

	struct i2c_client *client = to_i2c_client(st->dev);

	__be16 data = cpu_to_be16(val);

	int ret;



	return i2c_master_send(client, (char *)&data, sizeof(data));

	ret = i2c_master_send(client, (char *)&data, sizeof(data));

	if (ret < 0)

		return ret;

	if (ret != sizeof(data))

		return -EIO;



	return 0;

}



/**